The present invention relates to writing instruments, and in particular to writing instruments utilizing colored inks, pigments, and/or dyes in a suspended fluidic state.
Variable color writing instrument may include ball point pens with semi viscous ink, to pens with decreasing ink viscosity ranging from gel pens, roller ball pens, fountain pens, felt tip pens and the like. Applications may range from simple novelty reasons, to continuously blended color ink sketches, to more practical applications whereby a chronological indication may be given to a writing based upon the written word and the color of ink used. In endeavors which may involve skills, such as with color sketches, the ink colors throughout the sketch may be millions of colors, hues, and shades, and the user may create the sketch while controlling and anticipating the color(s) being blended and delivered to the writing tip. For example, while shades of yellow ink are delivered to the writing tip, the user may choose to sketch the sun or yellow objects, and as green ink is introduced, the user may sketch grass and green objects, etc.
In this sense, no two sketches would ever be the same. even if the act of sketching was exactly the same because color variation is inherently highly complex. In another example, notarizing documents or when dealing with legal matters, or even when writing a diary, the ink color of a writing may indicate the chronological order of such written words and the like. If insertions occur out of sequence, the color of such insertions may give an indication as to the general time period such insertions were made, and in this respect the use of color of ink may greatly assist in the prevention of improprieties and forgeries. It may be noted that re-blending an identical ink color would be very difficult, and thus forensic document examination may be greatly facilitated. Furthermore, in addition to ink, fluorescent dyes which fluoresce under ultraviolet light or other unusual lighting may be introduced into one or more of the ink colors, such that enhanced color graduations may be visible under UV light.
When dealing with writing fluids such as inks, paints, dyes, and/or pigments, subtractive color theory applies, as opposed to additive color theory where a light source passes through colored filters. Subtractive color theory is that of mixing inks, paints, dyes and/or other natural pigments to make colors that absorb and reflect particular wavelengths of light. For example, for printing, cyan, magenta, and yellow are primary colors. Black may be added for various reasons in a four-color process, most importantly because cyan, magenta, and yellow do not produce “pure” black but more of a dark gray.
Subtractive color theory is based on what light is absorbed. The amount of any color showing will depend on the amount of each of the three primary colors is in a color mixture. Cyan is the opposite of red. Magenta is the opposite of green. Yellow is the opposite of blue. The amount of blue in the final color mixture is directly related to the amount of yellow ink that is in the color mixture. The same is the case for other primary colors. For example, orange is a common color that is generally equal amounts of red and yellow. Adding more yellow will create a lighter orange. Adding red will create a red orange. Green color is a combination of cyan and yellow.
The subtractive color theory starts with the presence of all colors of light, usually as white light reflected from a white surface, such as paper. Dyes or inks may be used to subtract some of the reflected light. Understanding subtractive color theory requires an understanding of how colors of light are subtracted. If yellow dye or ink is applied on a white sheet of paper, one may think that color is added to the paper, but the color is already there; the white paper reflects all colors of light approximately equally. The yellow ink, however, reflects only red and green light and absorbs blue light, thereby subtracting it from the white light. Any color of ink, dye or paint subtracts its complementary color of light. Cyan ink on white paper absorbs red light, and allows green and blue to be reflected. Magenta ink subtracts green light, and allows red and blue to reflect. Yellow ink absorbs blue light, allowing red and green to reflect. Cyan, magenta and yellow are the subtractive primary colors, and combined in pairs, they produce the colors red, green and blue. When all three primary colors are subtractively combined, they subtract all colors of light, leaving black, typically a dark gray is the practical result.
When two primary colors are overlaid, they each subtract one color, allowing only the third color to be reflected. For example, if magenta and yellow ink are mixed or applied on white paper, the magenta ink absorbs green light. The yellow ink subtracts blue light. Neither of them absorbs red light, so red light is reflected by white paper, and a viewer sees the color red. In a sense, the colors experienced in a subtractive color mixture are created in the same way they're created with an additive mixture. A combination of red and green light (where the red and green colors each contain light from one-third of the spectrum) will always produce a yellow-colored light (containing light from two-thirds of the spectrum). It doesn't matter whether one starts with white light and subtracts one-third of the spectrum or starts with no light (black) and adds two thirds of the spectrum. Similarly, green and blue light always combine to produce cyan-colored light, and red and blue light always combine to produce magenta-colored light. Complementary colors work in similar ways for both additive and subtractive mixtures. In additive mixtures for example, yellow and blue light combine to complete the spectrum, producing white light. In subtractive mixtures, however, yellow and blue produce black (yellow and cyan produce green). Yellow ink subtracts one-third of the spectral light, blue ink subtracts the other two-thirds of the light, resulting in a black color. As previously noted, black is difficult to achieve in the subtractive process, and for that reason a four-color process may be desired in some situations in order to achieve a true black color.
In summary, the subtractive color system involves colorants and reflected light. Subtractive color starts with an object (often a substrate such as paper or canvas) that reflects light and uses colorants (such as inks, pigments or dyes) to subtract portions of the white light illuminating an object to produce other colors. If an object reflects all the white light back to the viewer, it appears white. If an object absorbs (subtracts) all the light illuminating it, no light is reflected back to the viewer and it appears black.